Why Native Plants
by Dan Walton
In a more perfect world, developers and builders would remove the absolute minimum number of plants possible from a building site. This has rarely been done in the past, nor does it seem likely to be done very frequently in the future. Consequently, instead of having a landscape that had developed in situ without attention, pampered nursery-grown plants are brought in to landscape properties that will have been considerably altered from their original state. The question is what kind of plants will be able to survive and thrive in the altered environment with minimal inputs of water, fertilizer and pesticides.
One answer would be to put back most if not all of the plants that were present on the site before construction. Since construction will most likely have changed the soil composition and drainage as well as light patterns, the plants that thrived before construction may no longer be the best suited for their previous sites. If you are interested in plants that can thrive without a lot of help, however, you will have to carefully select those that can meet such requirements. Plants native to this area of Florida have evolved mechanisms over the centuries that enable them to handle our climate. Hot dry weather in the spring, followed by even hotter wet and humid summers in infertile soils, is a regime that many non-native plants find difficult unless considerable external inputs are employed. In addition, native trees have had to be able to withstand the frequent hurricanes and tropical storms to which Florida is prone.
It has been argued that while native plants can survive well under undisturbed conditions, the proof for their superior survival under the disturbed conditions of a building site has not been obtained. While rigorous proof for their superior survivability may be lacking, native plants have at least evolved under the difficult Florida climate that alternates drought with flooding, and they have grown in soils with limited fertility under natural rainfall. Plants not native to this area may lack the ability to thrive here without large inputs of water and fertilizer, and may be overly prone to disease. As always, plants should be selected for their ability to thrive on the particular microsite.
An important attribute of native plants is that they are necessary in maintaining populations of many types of native fauna including birds, butterflies and a wide variety of crucially important insect pollinators. In Britain it has been found that native trees such as oak and hawthorne support several hundred invertebrates. The widely planted imported horse chestnut supports only four invertebrates in Britain, although a hundred or more colonize it in its native Mediterranean area. These invertebrates are food sources for birds and other wildlife, and the replacement of native species with introduced ones can disrupt many food chains. As more land is developed, urban and suburban areas become more important for wildlife.
Another important role for native plants in urban areas is aesthetic and more subjective. We obtain our sense of place in many instances from the flora without even knowing the identity of the plants. One of the ways we know we are in Florida and not in Ohio, other than the absence of winter snow, is the presence of massive live oaks and stately cabbage palms as well as other less well-known plants. Non-native plants have their place in our urban spaces, but surely the almost total replacement of our native flora with exotics is comparable to replacing all of our native birds with species of parrots because we enjoy their colorful plumage.